Remove JAX_RANDOM_WEIGHTS

[kyuyeunk]

Description

• Same functionality can be achieve with vllm argument --load-format=dummy
• It is better to remove duplicate configs to avoid confusion from users
• Similar PR: Remove SKIP_JAX_PRECOMPILE #1018

Tests

https://buildkite.com/tpu-commons/tpu-inference-ci/builds/4948

Checklist

Before submitting this PR, please make sure:

• I have performed a self-review of my code.
• I have necessary comments in my code, particularly in hard-to-understand areas.
• I have made or will make corresponding changes to any relevant documentation.

[github-actions]

Description

Start with a short description of what the PR does and how this is a change from
the past.

The rest of the description includes relevant details and context, examples:

• why is this change being made,
• the problem being solved and any relevant context,
• why this is a good solution,
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• shortcomings of the solution and possible future improvements.

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FIXES: b/123456
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Tests

Please describe how you tested this change, and include any instructions and/or
commands to reproduce.

Checklist

Before submitting this PR, please make sure:

• I have performed a self-review of my code.
• I have necessary comments in my code, particularly in hard-to-understand areas.
• I have made or will make corresponding changes to any relevant documentation.